1. Field of the Invention
This invention relates to a cassette loading device and more particularly to a device having a cassette holding member arranged to be shiftable between a first position in which the cassette is attachable to and detachable from the holding member and a second position in which the cassette is stayed in a state of allowing use of a recording medium disposed within the cassette.
2. Description of the Related Art
Heretofore, in many of video cassette recorders (hereinafter referred to as VCR), cassette holders have been provided with some means for preventing incorrect insertion of a tape cassette from the rear end thereof or in a reversed state. For example, it is known to provide a notched part in the lower side of the cassette in such a way as to extend in the cassette inserting direction and to open only on the front side. Meanwhile, the cassette holder is provided with a projection which is arranged on th bottom plate thereof to plunge into the above-stated notched part of the cassette. With the cassette holder arranged in this manner, the projection of the holder plunges into the notched part of the cassette to permit the cassette to be inserted into the holder only when the cassette is correctly inserted. In the event of an incorrectly inserting attempt, an end part of the cassette abuts on the projection to prevent the insertion.
Meanwhile, if the position of the upper surface of the cassette is entirely unrestricted in relation to the cassette holder, the cassette might be incorrectly inserted into the holder by riding over the projection of the latter. To avoid this trouble, therefore, the position of the upper surface of the cassette is generally restricted relative to the cassette holder. However, with such positional restriction imposed, not only the incorrect insertion but also the correct insertion of the cassette must be carried out under this restriction. As a result, latitude in allowing the vertical movement of the cassette relative to the holder is limited in this instance. In other words, the latitude is not allowed to exceed the depth of the notched part provided in the cassette.
In carrying out a recording or reproducing operation on a tape with an apparatus such as a VCR by pulling out the tape from the cassette, it is necessary to accurately set the cassette in position relative to the base plate of the apparatus. To meet this requirement, it has been practiced to precisely position the cassette relative to the apparatus by means of a positioning member mounted on the chassis of the apparatus. In that instance, with the latitude limited in allowing the cassette to move in the vertical direction relative to the holder as mentioned above, the cassette holder also must be positioned on the body of the apparatus in a degree of precision corresponding to the depth of the above-stated noched part. This means a requirement for an extremely high degree of machining precision. Further, to meet that requirement, it is necessary to use some rigid material for the body of the holder at the expense of a desire to reduce the weight of the apparatus.
Further, in positioning the cassette holder on the apparatus body, an engaging part which is arranged on the side of the holder to be urged toward the cassette inserting position from the cassette using position thereof is locked to the apparatus body in general. However, in order to lock the engaging part, the cassette holder must be once moved passing over the cassette using position (over-stroke). The extent of this over-stroke is determined also by the above-stated latitude allowed to the vertical movement of cassette within the cassette holder.
Generally, the cover of the cassette is arranged to be automatically pushed up when the cassette holder is pushed down from a cassette inserting position to a cassette using position. However, if the cassette holder is suddently pushed down by hand without having the above-stated position restricting arrangement, the cassette might be moved upward by the above-stated cover lifting force away from the bottom plate of the cassette holder within the holder. In that instance, if the cassette is moved in parallel with the bottom plate even to a slight extent, the cassette rides on the above-stated projection. Under such a condition, even if the cassette holder is in the cassette using position, the tape does not satisfactorily travel because the reel hub of the cassette fails to perfectly engage the reel of the VCR. Further, in that event, the tape tends to be damaged by an inaccurately positioned state of the tape relative to a capstan, etc.